While working on my old tractor I ran across this flowchart. It's an unusual troubleshooting format (at least to me), but couldn't be any simpler or more informative. What we need is for V8 Bob to do a flowchart for brake problems! Hope this is helpful to someone.
Good point at which to remind people that there are 2 common wiring schemes for the 3 terminal regulator systems, HD circuit used on Fords (6 and 12) and light duty circuit used by GM and many others. The above is non-Ford, so at the box numbered "3" jump F to A rather than ground!! Print it off, but add a correction if you have Ford generator!